The purpose of the proposed work is to obtain information on gastrointestional function by means of measuremnts of production and absorption of volatile compounds in the blood. The studies to be performed include: 1. Measurements of the intestinal absorption of various carbohydrates in various disease state utilizing breath hydrogen (H2) excretion as an indication of carbohydrate malabsorption. 2. Assessment of unstirred layers in the gut utilizing the absorption of carbon monoxide as a measure of the diffusion barrier in the gut. 3. Study the volatile prodcts produced by fecal homogenates when exposed to ethanol.